Refrigeration



5 'Sheets-Sheet www T. M. ELFVING REFRIGERATION Filed Sept. 6, 1928 Dec. 22, 1931.

Dec. 22, 1931. T. M. ELFVING 1,837,767

REFRIGERATION Filed sept. e, 192s 5 sheets-sheet 2 "ari Dec. 22, 1931. T M ELFV|NG v1,837,767

REFRIGERATION Filed Sept. 6, 1928 5 Sheets-Sheet 3 ENTQR BY i i y? Paienfed Dec. 22, 1931 e UNITED STATES lPATENT OFFICE THORE MARTIN ELFVING, F STOCKHOLM, SWEDEN', ASSIGNOR TO ELECTROLUX SERVED' CORPORATION, 0F N'EW YORK, N. Y., A CORPORATION 0F DELAWARE REFRIGERATION Application led September 6, 1928, Serial No. 804,188, and in Germany April 24, 1928.

The present invention relates to refrigeration and particularly to evaporators for use y in domestic refrigeration cabinets. Still lll more particularly, the invention relates to the type of automatic refrigerating apparatus wherein a pressure equalizin iuid is used in the presence of which the re rigerant evaporates. p p

In domestic refrigerators as at present built a part of the cold produced is utilized for freezing ice, for which purpose a teml I this decreases the efficiency which to a great extent depends upon the' temperature at which the evaporation takes place and which decreases as the temperature decreases.

The object of the present invention is. to provide an evaporator comprising means for `distributing the cold produced in such a manner that only the cold necessary for the ice production is produced at the low temperature required therefor, while the second part of the cold produced and utilized for maintaining the temperature in the cabinet is obtained by evapora-tion at a higher temperature, as a result of which a considerable improvement in the eiciency of the apparatus is obtained. A further. object of the invention is 4to provide improved structure for so distributing theJ production of refrigeration as to give eilicient distribution and eiicient heat exchange. The invention will be apparentfrom the followingdescription taken in connection with the accompanying illustrative drawings, wherein:

Fig. 1 is a more or lessdiagrammatic illustation of a refrigerating system ofthe ,absorption type embodying the invention;

Fig. 4 is a view looking down on` acasting l forming part of the evaporator assembly;

Fig. 5 is a cross-sectional View of a modified form of evaporator; and Fig. 6 is a. front View of' the apparatus shoWI'finF ig. 5.

erence character 10 designates a generator lwhich is heated by any suitable means, as for instance, the gas burner l1. Generator 10 consists ,of an upper annular chamber 12 which may be considered as the main gen- Referring more particularly to Fig. 1, referator and a lower annular chamber 13 which maybe considered as the auxiliary generator and which are separated from each other by the partition 14. The central space 15 of the generator is a iue for the hot Gases of com'- bustion. A conduit 17, the grlater part of which is outside of the generator proper, leads from chamber 13 to chamlier 12. The lower end of conduit 17 extends within chamber 13 to a point some distance below the normal level at which the liquid is maintained therein. A hole o r port 18 is provided in the side of conduit 17 which, in operation, is slightly above the7 liquid level in chamber 18, and which ldetermines the level of liquid therein. The bottom of conduit 17 is open providing a lower end opening for conduit 17 within the auxiliary generator. l The up er end of conduit 17 communicates with cham r 12.'

A conduit 22 communicates with the upper end of the ,upper chamber 12 of generator 10. Fins 23 are preferably provided on conduit 22 which increase the radiating area thereof. Conduit 22 passes through water jacket 24, thence through con-duit 25, heat exchanger 26 and conduit 27. It ends in aigoose neck 28 in the top of evaporator 29. Evaporator 29 comprises a cylindrical member. 30 in which are located baiiies 31 which are provided with holes 32 around which are rims A 33. The holes in adjacent baliies are preferably staggered as shown. A conduit 34 leads from the bottom of member 30 to heat exchanger 26. Heat exchanger 26 consists of acylindrical member 35 near the ends of which are located two heads 36 and 37 containing drain holes and 56. A conduit 27 leads from the space 38 formed between head 37 and one end of the heat exchanger to the top of evaporator 29. A number of tubes 39 connectspa'ce 38 with space 40which latter' space is formed between head 36 and the other end of the heat exchanger. Conduit 25 connects the top of an absorber 4l with space 40. Evaporator member 29 communicates by means of conduit 34 with space 42 which surrounds tubes39 and is included between heads 36 and 37. .Conduit 43 connects spacev 42 with the bottom of absorber 41. Absorber 41' consists of a hollow cylindrical -member 44 which is supplied with bafiies 45 which may be similar to bafl'les 31 in evaporator 29. It is 'also surrounded by a water'jacket 46 which is supplied with cooling water through conduit 47 and discharges it through conduit 48 to water jacket 24 from whence the cooling water is finally discharged through conduit 49. A conduit 50 leads from the bottom of absorber. 41 to near the top of chamber 13 in generator 10. Another conduit 51 'leads from near the lbottom of chamber 12 vabsorbing liquid is'water but it is to be understood that th'e use of other refrigerants and absorbing 'media is contemplated. Application of heat to the solution in chamber 12 serves to drivethe ammonia out of solution as a vapor. Vaporous ammonia passes upwardly through conduit 22. Fins 23 serve to cool a port`ion of conduit 22 wherein any water vapor which may be mixed with the ammonia vapor is liquefied and runs back to chamber 12. This cooling effect is not sufficient, however, to liquefy the ammonia and L it passes to that portion of conduit 22 which is surrounded and cooled by Water jacket 24. Here the'ammonia is liquefied and passes thrpugh the remainder of conduit 22 tothe top of evaporator 29. In the evaporator refrigeration is produced due to the diffusion.

' of the ammonia into a gas, which is inert with respect to ammonia, for instance hydrogen, which is admitted through conduit 27. Baffles31 are provid-ed to aid this diffusion. As the mixtureof ammonia and hydrogen in evaporator29 has a greater specific weight than the hydrogen in conduit 27 the mixture will iow downwardly through the evaporator, through conduit 34, through the space 42 in heat exchanger 26, and through conduit 43 to the lower part of absorber 41. In theabsorberythe ammonia is absorbed by the water. Bafiles 45 are provided to aid in this absorption. The hydrogen is not absorbed by the water and passes upwardly through the absorber, through conduit 25, the tubes 39 in heat exchanger 26, and finally through conduit 27 to the top of evaporator 29. Within heat exchanger 26 liquid ammonia, hydrogen passing to the evaporator and the mixture of gaseous ammonia and gaseous hydrogen passing to the absorber are in heat exchange relation with each other.

The rich solution of ammonia in water passes out of the bottom of absorber 41 through conduit 50 to chamber i13 of generato'r 10. The application of heat to chamber 13 from burner 11 causes some of the liquid to vaporize and collect in the upper part of chamber 13. Alternate gas and liquid bubbles enter conduit 17 and a percolator effect is obtained which raises liquid into chamber 12. Weak liquor Hows through conduit 51 to the top of the absorber.

Surrounding evaporator shell 30, adjacent the top or gas inletJ end is a. east member 6() composed of two sections having semi-circular portions 61 extending outwardly`from box-like enclosures for the reception of ice trays 64 and having flanges 62 adapted to be pulledtogether by bolts 63 to firmly press member 60 around shell 30. The outside walls of member 60 are straight and of minimum heat transmitting area commensurate with the formation of enclosures. This holds in the coldand permits quick freezing of ice cubes. When front doors or plates are placed over the openings'of the enclosur s for the ice trays, the ice trays are comp etely enclosed.

' Cast member 60 is preferably made of light metal such as aluminum or an aluminum alloy. This casting is in heat exchange relatlollilwith the coldest part of the evaporator s e Below member 60 there is attached to shell the channels formed by the plates and extend beyond the plates at Ythe top and bottom. Bands 68 and 69 at the top and bottom, respectively, of member 65 serve to pull the bars 67 against the backs of the channels and the backs of the channels against the yao shell 30. Bolts 71 pull the bands 68 and 69 together. The bands should'be flexible.

It is essential for heat exchange that the channel-shaped plates be in close contact with the evaporator shell, there being a surface of contact at least double the thickness of the shell. The arrangement above described'gives a large surface in contact with atmosphere while at the same time giving a large surface of metal to metal contact. Bars 67 are preferably square or rectangular in cross-section or otherwise made so as to curve the backs of the plates against the shell 30.

Member and 65 are not in heat transfer relation except through the part of shell 30 between them. n

It will be seen that the cast member 60 and the air cooling member are interchangeably mountable along the length of the shell. The surfaceto which these members are attached may be termed the attachment surface. This attachment surface is uniformly shaped over substantially the length of they evaporator. A

Figs. 5 and 6 show a modified form of evaporator comprising a horizontal shell 72 to which liquid refrigerant is admitted from pipe 22, to which a gas is admitted through conduit 27 and from'which a gas mixture leaves through conduit 34. Member 75 isa cast member corresponding to cast member 60. It differs in that the ice trays pull out longitudinally of the shell instead of tra-nsversely thereto. Member 75 surrounds a part of shell 72 and fins 76 surround the remaining part. Trays 77 are formed with raised parts 78 to form pools of liquid.

Again, the coldest part of the evaporator is that where the equalizing gas enters and which is surrounded' by cast member 75. The

' liquid refrigerant enters the warmer part of the evaporator, flows the length of shell 30 on the uppermost plate 77, `thence over the next two lower plates in the cold part, thence` through opening 80 in Wall 8l andover plates in the Warmer part. Another hole 83 may be provided in the lower part of wall 8l through which liquidlefrigerant can again How into c the low temperature part.

Some of the raised parts 78 on trays 77 are made higher than others to prevent liquid from flowing over them. i In order to prevent heat exchange as far as possible, trays 77 are made thin and wall 8l is made double tol form an intermediate gas layer. n

The cast members 60 and 75 may be surrounded by insulating material.

By having the large surface of member 65, it has been found that the formation of frost on the evaporator can be substantially prevented. .4

It will be-understood that many variations are possible within thespirit and scope of the invention.

What is claimed is :L

1. In an absorption refrigerating apparatus of the type employing an inert gas in the presence of which the refrigerant evaporates, an evaporator comprising an elongated shell uniformly shaped exteriorlyA over substantially its entire length and a plurality -ofcooling elements of different characment surface of uniform contour, an enclosure forming member of restricted outer surface secured around one part of said shell and van air cooling member comprising a series of thin elements having large exposed surface secured to another part of said shell, said enclosure member and said air cooling member being interchangeably mountable on said shell. y

3. A refrigerator comprising a food storage compartment, an evaporator entirely within said compartment, said evaporator comprising a single shell having anattachment surface of uniform contour, an enclosure forming member of restricted outer surface secured around one part of said shell, means within said member for retaining ice freezing trays andan air cooling member comprising a series of thin 4elements having large exposed surface secured to another part of said shell, said enclosure member and said air cooling member being interchangeably mountable on said shell.

4. A refrigerator comprising a 'food storage compartment, an evaporator entirely within said compartment, said evaporator comprising a singleshell having'an attachment surface of uniform contour, an enclosure forming member of restricted outer surface secured around one part of said shell, means within said member for retaining ice freezing trays and an air cooling member comprising a series of thin elements secured to another part of said shell having sufficient 5. A refrigerator comprising a food' storage compartment, an evaporator in said compartment, said evaporator comprising a single shell having an attachment surface of uniform contour, means to produce a temperature in said shell below the freezing point of Water, an enclosure forming member secured around one part of said shell, 'said member having a sufficiently small outer surface so that a temperature below the freezing point of water will be maintained therein and an air cooling member comprising a series of thin elements secured to another part of said shell having sufficient surface for contact with the air in said food storage compartment so that the rate of heat transfer from the air to the elements will be fast enough to substantially prevent the formation of frost on the elements, saidenclosure 'member and said air cooling member being interchangeably mountable on said shell.

6. A refrigerator comprising a food storage compartment, an evaporator entirely Within said compartment, said evaporator comprising a single shell having an attachment surface of uniform contour, 'means to supply liquid refrigerant to said shell, means to supply an inert gas to one `end of said shell, means to Withdraw fluid from the other end of said shell, an enclosure forming 'member of restricted outer surface secured around said shell adjacent the end of supply of inert gas, means within'saidmember for retaining ice freezing trays and an air cooling member comprising a series of thin elements secured to another part of said shell having sufficient surface for contact with the air in said food storage compartment so that the rate of heat transfer from the air to the elements will be lfast enough to substantially prevent the formation of frost on theelements, said enclosure member and said air cooling member being interchangeably mountable on said storage compartment, an evaporator entirely Within said compartment, said evaporator comprising a single shell having an attachment surface of uniform contour, means t0 supply liquid refrigerant to said shell, means to supply an inert gas to one end of said shell, means to withdraw fiuid from the other end of said shell, an enclosure forming member of restricted outer surface around one portion of said shell, means within said member for retaining ice freezing trays and an air cooling member comprising a series of thin elements secured to another part of said shell having sufficient surface for contact with the air in said food storage compartment so that the rate of heat transfer from the air to the elements will be fast enough to substantially prevent the formation of frost on the elements, said enclosure member and said air cooling member being interchangeably mountable on said shell. l

8. An evaporator comprising a cylindrical shell of substantially uniform diameter throughout its length and having a gas supply end and a gas discharge end, a plurality of members-within said'shell for distributing liquid, means to supply liquid refrigerant to said shell, means to supply an inert gas to said shell at the gas supply end, means to Withdraw fluid from said shell at the gas discharge end, a cast member clamped around said shell nearer the gas supply end forming enclosures for the reception of ice trays and having a relatively small amount of surface contacting the atmosphere and an air cooling member comprising a large number of thin plates secured to and extending outwardly from said shell nearer the gas discharge end and having a large surface contacting the atmosphere, said plates being channel-shaped with their backs against the shell, said cast member and said air cooling member being interchangeably mountable on said shell.

9. An evaporator comprising a shell of substantially uniform diameter-throughout its length" and having a gas supply end and a gas discharge end, a plurality of members within said shell for distributing liquid, means to supply liquid refrigerant to said shell, means to supply an inert gas to said shell at the gas supply end, means to withdraw fluid from said shell at the gas discharge end, a cast member clamped around said shell nearer the gas supply end forming enclosures for the reception of ice trays and having arelatively small amount .of surface contacting the atmosphere, said plates being channel-shaped with their backs against the shell, bars in the channels and means for pulling the bars against the backs of the channels and the backs of the channels against the shell.

10. An evaporator comprising a shell having an attachment surface of uniform contour, "a plurality of members within said shell for distributing liquid, means to supply liquid refrigerant to said shell, means to supply an inert gas to said shell, means to withdraw fluid fromsaid shell, a cast member clamped around one part of said shell forming enclosures for the reception of ice trays and having a` relatively small amount of surface contacting the atmosphere and an air cooling member comprising a large number of thin plates extending outwardly from another part of said shell having a relatively large surface contacting the atmosphere, said plates being channel-shaped with their backs against the shell, said cast member andsaid air cooling member being interchangeably mountable on said attachment surface.

11. An evaporator comprising a shell, a plurality of members within said shell for distributing liquid, means to supply liquid refrigerant to said shell, means to supply an inert gas to said shell, means to withdraw fluid from said shell, a cast member clamped around one part of said shell forming enclosures for the reception ofice trays and having a relatively small amount of surfacecontacting the atmosphere, a large numbery of thin plates extending outwardly from another part of said shell having a relatively large surface. contacting the atmosphere, said plates being channel-shaped with their backs against the shell, bars in the channels and means for pulling the bars against the backs of the channels and the backs of the channels against the shell.

l2. An evaporator comprising a shell having an attachment surface of uniform contour, a plurality of members within said shell for distributing liquid, means to supply liquid refrigerant to said shell, means to supply an inert gas to said shell, means to withdraw fluid from said shell, a cast member clamped around one portion of said shell forming enclosures for the reception of ice trays and having a relatively small amount of surface contacting the atmosphere and an air cooling member comprising a large number of thin plates extending outwardly rfrom another portion of said shell having a relatively large surface contacting the atmosphere, said cast member and said air cooling member being interchangeably mountable on said attachment surface.

13. An evaporator comprisinga shell having an attachment surface of uniform contour, a plurality of members within said shell for distributing liquid, means to supply liquid refrigerant` to said shell, means to supply an inert gas to one end of said shell, means to .withdrawfluid `from the other end of said shell, a casting clamped aroundsaid shell adjacent the end of supply of inert gas forming enclosures for the reception of ice trays and having a relatively small amount of surface contacting the atmosphere and an air cooling member comprising a large number of thin plates extending outwardly from said shell adjacent the en is withdrawn and having a relatively large surface contacting the atmosphere, said cast member and said air cooling member being interchangebly mountable on said attachment surface.

14. An evaporator comprising a cylindril of restricted outer surface secured around the shell nearer the gas supply end and a series of thin elements having large exposed surface secured around the shell nearer the gas discharge end, said member and said elements being interchangeably mountable on said shell.

In testimony whereof I affix my signature.

THORE lWARTIN ELFVING.

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